Compact underground gis for high-voltage gas-insulated substation (gis), busbars and lines (gil)

ABSTRACT

The invention relates to a modular and compact arrangement ( 200 ) of three phases (A, B, C) of a gas-insulated apparatus ( 100 ), that is suitable for placement inside a tunnel or a pipe ( 106 ) or another confined space. According to the invention, the three phases (A, B, C) are arranged in a triangle or side-by-side on a fixation part ( 103, 104 ) which includes a roller system ( 105; 105   a,    105   b   , 105   c,    105   d ). This allows the insertion of such a three-phase assembly ( 100 ) into confined spaces such as pipes or tunnels ( 106 ), without the need for access by workers or machinery. Furthermore, the present disclosure relates to a method for assembling and installing such a three-phase arrangement ( 100 ) into the confined space ( 106 ).

FIELD OF THE INVENTION

The present disclosure relates to the field of high-voltage andmedium-voltage gas-insulated switchgear (GIS), gas-insulated busbars andgas-insulated lines (GIL). A modular and compact arrangement of threephases of a gas-insulated apparatus is disclosed, that is suitable forplacement inside a tunnel or a pipe or another confined space.Furthermore, the present disclosure relates to a method for assemblingand installing such a three-phase arrangement into the confined space.

BACKGROUND OF THE INVENTION

JP9121437A2 was first published on Jun. 5, 1997 in the name of HitachiLtd. It relates to a gas-insulated transmission line (GIL) in a largecircular tunnel. Two linearly arranged three-phasesingle-phase-encapsulated GILs are fixedly installed in the tunnel. Atrench is provided in the center of the tunnel floor. It serves forproviding a work space and equipment storage space for personnel. Thetrench may also prevent water infiltration of equipment in the tunnel,may be used to store or install a further GIL, and may house an exhaustpipe and a water distribution pipe. A transfer carriage for installingGIL enclosures is movable on the floor above the trench.

JP51685, first published 1976, also discloses a large accessiblecircular tunnel that serves for installing and housing electric cables.The tunnel contains multiple three-phase triangular cable systemsarranged in two vertical stacks. The tunnel is cooled via hoses that areconnected to a cooling system.

CN10620781A was first published on Jul. 12, 2016 in the name of ChinaWestern Electric Co. It relates to installation methods for rigidgas-insulated transmission lines (GIL) in large half-circular tunnelshaving rails for movement of transport vehicles and of mounting vehiclesequipped with support arms for supporting and moving the GIL. Duringinstallation, wheels provide relative movement between the transport andmounting vehicles and a transfer cart and further between the transfercart and the GIL. These wheels are blocked during transportation of theGIS on the transport and mounting vehicles through the tunnel.

CN203933009U was first published on May 11, 2014 in the name of NationalGrid Corporation et al. It relates to an AC ultra-high-voltagecross-river power transmission system in a large accessible tunnel. TheGIL can be installed in a straight line or in a vertical V-shaped line.In the V-shaped line, two sections of the GIL are connected by elbows.The GIL is filled with SF₆ gas or SF_(6/)N₂ gas mixture or compressedair. Pipeline wells are positioned on both water banks and can be in theform of vertical or inclined wells.

In the known tunnel installations, the three phases may be placed on thesides of the tunnel (one above each other); at the bottom of the tunnel(e.g. above pavement or below pavement) or on top of the tunnel(enabling access for people or machinery on ground), and additionalspace for personnel is provided inside the tunnel. Therefore, much spaceis needed and contributes to the cost of building the tunnel, whichincreases with the square of the tunnel diameter. Rectangular tunnelscan be used for side-by-side arrangements of three phases. Again, muchspace is needed for providing personnel with equal access to each phaseduring installation, maintenance or repair of the gas-insulated line.

SUMMARY OF THE INVENTION

Therefore, it is an object of the invention to provide an improvedgas-insulated line or line-segment module thereof, which is particularlysuitable for arrangement in a tunnel and allows to keep the requiredspace for accessibility, assembly, disassembly and maintenance of thegas-insulated line to a minimum.

These objects are achieved by the subject-matter of the independentclaims. Some embodiments as given in the dependent claims and claimcombinations provide further improvements.

According to the invention, a gas-insulated line has a longitudinalaxis, comprises phases with single-phase enclosures that are alignedparallel to one another, and is segmented into line segments having asegment length, wherein at least one of the line segments comprises: atleast one holding means arranged at at least one longitudinal positionof the line segment for holding the single-phase enclosures of the linesegment relative to one another, thereby mounting the single-phaseenclosures of the line segment together and forming a unitaryline-segment module.

Such a gas-insulated line has various advantages over known systems. Byforming line-segment modules directly from a holding means and threesinge-phase enclosures very compact modules can be created. Suchline-segment modules can have reduced lateral or radial spacerequirement and can easily fit e.g. into narrow confined spaces such aspipes or tunnels. Furthermore, the provision of unitary line-segmentmodules allows to create units, that are separately handable andmovable, e.g. on the construction site or inside an installation pipe ortunnel. The unitary line-segment modules are mechanically stable, inparticular in length direction, for being pushed into or dragged out ofa pipe or tunnel. This largely simplifies the construction ofgas-insulated lines and their installation in confined spaces such asunderground pipes or tunnels. In addition, the confined space can bereduced in size and less time and cost for groundwork is needed.

Very good results can be achieved by providing a first holding means ata first longitudinal position of the line segment for holding thesingle-phase enclosures of the line segment relative to one another atthe first longitudinal position, a second holding means at a secondlongitudinal position of the line segment for holding the single-phaseenclosures of the line segment relative to one another at the secondlongitudinal position, and thereby mounting the single-phase enclosuresof the line segment together and forming the unitary line-segmentmodule. This further improves the mechanical stability of the unitaryline-segment module.

Very good results can be achieved by providing the line-segment modulewith moving means for facilitating movement of the line-segment module,in particular by exerting a pushing or dragging force onto theline-segment module at a longitudinal end position of the line-segmentmodule. In particular, the moving means comprise or are rollers forsupporting and moving, in particular pushing or dragging, theline-segment module.

In embodiments, the moving means can be arranged in each holding meansand/or can be adapted to support and allow rolling the line-segmentmodule in the confined space, in particular a confined space that is notaccessible for personnel in upright position or is inaccessible topersonnel.

In embodiments, the moving means, in particular rollers, can be mountedin each holding means such that an outer contour of the moving means isadapted to a bottom of a confined space, in particular adapted to arounded bottom of a pipe or a flat bottom of a tunnel.

In embodiments, the moving means, in particular a first roller and asecond roller in each holding means, can be mounted permanently on theline-segment module. Furthermore, the moving means can be mounted for:inserting the line-segment module into the confined space duringinstallation, and/or for removing the line-segment module out of theconfined space for maintenance or repair, and/or for compensatingthermal expansion during operation of the gas-insulated line.

In embodiments, the gas-insulated line can comprise three phases withsingle-phase enclosures, wherein the holding means, in particular thefirst and second holding means, hold the three phases in a triangulararrangement.

In embodiments, the gas-insulated line can comprise three phases withsingle-phase enclosures, and the holding means, in particular the firstand second holding means, hold the three phases in a linear arrangement.

In embodiments, each single-phase enclosure of the gas-insulated linecan comprise a first enclosure tube and a second enclosure tube, bothhaving a longitudinal axis and a radial thickness, and therebetween aconnection portion for providing a gas-tight connection between a firstend of the first enclosure tube and a second end of the second enclosuretube, wherein the connection portion provides a sealing element betweenthe first end and the second end in such a manner that a gas-escape pathis sealed in a gas-tight manner, the gas-escape path is formed betweenthe first end and the second end and starts at an inside of the firstand second enclosure tube and ends at an outside of the first and secondenclosure tube, the gas-escape path has a first segment running along adirection having a directional component parallel to the longitudinalaxis, and the sealing element is provided in the first segment.

Such designs allow to prolong the gas-escape paths, or the gas-escapepaths which are minimal in radial direction (when seen in the centrallength cross section of the enclosure), between the ends of theenclosure tubes and thereby to improve the sealing without increasingthe radial extent of the integrated flange design. Furthermore, thepartially axial orientation of the gas-escape path can allow to provideplural sealing rings in series along the gas-escape path.

In embodiments, thermal expansion of the gas-insulated line inparticular during operation can be compensated by providing: a firstlongitudinal fixation position, in particular first end position, atwhich the gas-insulated line is fixedly mounted to a first referencelocation, a second longitudinal fixation position, in particular secondend position, at which the gas-insulated line is fixedly mounted to asecond reference location, there-between a length compensation elementbeing arranged in the gas-insulated line, in particular between twoline-segment modules, and the moving means, in particular rollers, ofthe line-segment modules, which are arranged between the first andsecond longitudinal fixation positions, being unblocked for allowing formovements due to thermal expansion or contraction of the gas-insulatedline between the first and second longitudinal fixation positions.

In embodiments, a flexible-angle unit is present in the gas-insulatedline, in particular between two line-segment modules, to provide anon-straight gas-insulated line.

The invention also relates to a line-segment module for a gas-insulatedline, in particular for a gas-insulated line as disclosed herein, theline-segment module having a segment length and comprising: phasesencapsulated by single-phase enclosures that are aligned with oneanother, at least one holding means arranged at at least onelongitudinal position of the line-segment module for holding thesingle-phase enclosures of the line segment relative to one another,thereby mounting the single-phase enclosures together to make a unitaryline-segment module.

In embodiments of the line-segment module, the holding means can be orcomprise: a first holding means at a first longitudinal position of theline-segment module for holding the single-phase enclosures relative toone another at the first longitudinal position, a second holding meansat a second longitudinal position of the line-segment module for holdingthe single-phase enclosures relative to one another at the secondlongitudinal position, and thereby mounting the single-phase enclosuresof the line segment together and forming the unitary line-segmentmodule.

In embodiments, the line-segment module can comprise or be at least oneof: gas-insulated busbar; gas-insulated connection element;gas-insulated switchgear (GIS) such as disconnectors, circuit breakers;or other electrical component.

In another aspect, the invention relates to a system comprising agas-insulated line having line-segment modules, in particular agas-insulated line as disclosed herein, and a confined space providing avolume for accommodating the gas-insulated line.

In embodiments of the system, the confined space is connected to atleast one manhole that is or are accessible by personnel for installing,maintaining and/or removing line-segment modules.

In embodiments of the system, the at least one manhole is at a startingposition, an end position, and/or an intermediate position of thegas-insulated line and has a manhole length that is larger than thesegment length of the line-segment module, in particular the manholelength being larger than 6 m or 8 m or 10 m.

In embodiments of the system, the gas-insulated line is in amulti-lateral arrangement of the phases, preferably a star-shapedtriangular arrangement three phases, in particular as disclosed herein,and the confined space has a clear cross section having an at leastpartially rounded shape, e.g. an arched tunnel, or an at least partiallycircular shape, e.g. a circular pipe.

In other embodiments of the system, the gas-insulated line is in alinear arrangement of at least three phases, in particular a lineararrangement of three phases and optionally a reserve phase as disclosedherein, and the confined space has a clear cross section having a flatbottom.

In embodiments of the system, first critical transverse dimensions, inparticular an inner diameter or inner height or inner width, of a clearcross section of the confined space is larger than second criticaltransverse dimensions, in particular an outer diameter or outer heightor outer width, of a cross section of the gas-insulated line by lessthan 50%, preferred less than 30%, more preferred less than 20%, mostpreferred less than 10% of the cross section of the gas-insulatedmodules. In particular, the first critical transverse dimension, inparticular an inside diameter of the confined space, is approximately0.5 m for a 100 kV gas-insulated line and approximately 1.2 m for a 550kV gas-insulated line.

In a further aspect, the invention relates to a method for installing agas-insulated line, in particular a gas-insulated line as disclosedherein, in a confined space, the gas-insulated line having alongitudinal axis, comprising phases with single-phase enclosures andbeing segmented into line segments, the method comprising the methodelements of:

-   -   a. aligning three single-phase enclosures of a line segment,    -   b. fixing the three single-phase enclosures together by at least        one holding means, in particular by a first holding means at a        first longitudinal position of the line segment and by a second        holding means at a second longitudinal position of the line        segment, thereby forming a unitary line-segment module, and    -   c. connecting the line-segment module to an end of an already        assembled portion of the gas-insulated line arranged in a        confined space, e.g. a pipe or tunnel.

In embodiments, the method element c. comprises the method elements d.and e.:

-   -   d. inserting a formed or machined end of the line-segment module        into a formed or machined end of the already assembled portion        of the gas-insulated line for providing a flange-connection, and    -   e. securing the flange-connection by an elastically openable and        closable bracket, and optionally securing the bracket by a        securing bar and/or a heat shrink tube.

In embodiments, the method comprises the method elements of:

-   -   f. filling a gas volume of the three single-phase enclosures        with an insulation gas at an elevated gas pressure, in        particular air, SF₆, an alternative gas or gas mixtures, or a        combination thereof at an over-pressure in a range of 3 bar to 8        bar.

In embodiments, the method comprises the method elements of:

-   -   g. arranging a supply duct on top of the line-segment module and        connecting it to a mating end of a supply duct of the already        assembled portion of the gas-insulated line, and/or    -   h. providing moving means, in particular rollers, permanently        mounted on the at least one holding means.

In embodiments, the method comprises the method elements of:

-   -   i. moving or rolling the gas-insulated line (100) with the        connected line-segment module (102) by a pushing or dragging        force into the confined space (106), and in particular    -   j. repeating steps a. to i.

In embodiments, the method can also comprise method elements ofde-installing the gas-insulated line, e.g. by performing the methodelements a. to i. in a reversed manner.

In embodiments of the method, the moving means, in particular rollers,are used for at least one of: inserting the line-segment module into theconfined space during installation, removing the line-segment module outof the confined space for maintenance or repair, and compensatingthermal expansion after installation or during operation of thegas-insulated line.

In this application, the terms “radial”, “axial”, “central length crosssection”, circumferential” refer to a longitudinal axis z of theenclosure, or in other words to a substantially cylindrical shape orsymmetry of the enclosure.

It is to be understood that both the foregoing general description andthe following detailed description present embodiments with optionalfeatures, and are intended to provide an overview or framework forunderstanding the nature and character of the disclosure. Theaccompanying drawings are included to provide a further understanding,and are incorporated into and constitute a part of this specification.

The drawings illustrate various embodiments, and together with thedescription serve to explain in examples the principles and operation ofthe concepts disclosed.

BRIEF DESCRIPTION OF THE DRAWINGS

The herein described invention will be more fully understood from thedetailed description given herein below and the accompanying drawingswhich should not be considered limiting to the invention described inthe appended claims. The drawings are showing various embodiments,namely in:

FIG. 1 a cross-sectional length view of a system comprising agas-insulated line in a multilateral, in particular triangular,arrangement of phases arranged inside an underground tube;

FIG. 2 a cross-sectional view of a triangular arrangement of threesingle-phase-encapsulated gas-insulated lines and a supply duct arrangedin a tube;

FIG. 3 a perspective view of a triangular fixation with a three-phasefixation element and rollers;

FIG. 4 a front view of the embodiment of FIG. 3 in a tube;

FIG. 5 a front view of a triangular fixation with a three-phase fixationelement and spring-loaded rollers;

FIG. 6 a cross-sectional length view of a system comprising agas-insulated line in a linear arrangement inside an undergroundrectangular tunnel;

FIG. 7 a cross-sectional view of a linear arrangement of threesingle-phase-encapsulated gas-insulated lines in a tunnel;

FIG. 8 a perspective view of a linear fixation with a three-phasefixation element and rollers;

FIG. 9 a detail view showing a partial cross-sectional length view of anintegrated flange design; and

FIG. 10 a cross-sectional length view of a length compensation element.

DESCRIPTION OF THE EMBODIMENTS

Reference will now be made in detail to certain embodiments, examples ofwhich are illustrated in the accompanying drawings, in which some, butnot all features are shown. Embodiments disclosed herein may be embodiedin many different forms and should not be construed as being limiting;rather, these embodiments are provided so that this disclosure willsatisfy applicable legal requirements. Whenever possible, like referencenumbers will be used to refer to like components or parts.

FIG. 1 shows a lengthwise cross-sectional overview of a system 200comprising a single-phase-encapsulated gas-insulated line 100, inparticular a straight busbar duct 100 thereof, arranged in a tunnel orpipe 106. The gas-insulated line 100, or generally gas-insulatedapparatus 100, have single phase enclosures that can be in amultilateral arrangement, e.g. in a triangular star arrangement 101A,101B, 101C of three phases A, B, C as shown in FIG. 2 , or alternativelyin a quadrilateral arrangement of phases (not shown) comprising three(active) phases A, B, C and a reserve phase, or in a pentagonalarrangement (not shown) comprising three (active) phases A, B, C, areserve phase and an additional space for receiving a supply duct forother media.

In embodiments, even more phases, e.g. in a double busbar configuration,are possible and can be arranged in the tunnel or pipe 106. For example,six or seven phases (e.g. including a reserve phase) can be arranged ina pentagon or hexagon (i.e. largely on a circle) and/or with anadditional phase in the center for installation in a pipe.Alternatively, six or seven phases can be arranged in a linearside-by-side arrangement or in two triangular arrangements arrangedside-by-side in a more flat tunnel.

FIG. 1 is now discussed in connection with FIG. 2 . The single-phaseenclosures 101A, 101B, 101C are separately gas-tight and preferably madefrom metal. Each enclosure 101A, 101B, 101C houses a central conductor12 that is suspended in its insulation gas compartments 13.

The gas-insulated line 100 can have a longitudinal axis z, which may bestraight or may include certain bents in horizontal and/or verticaldirection, depending on need or shape of the tunnel or pipe 106. Thegas-insulated line 100 can comprise three electrical phases A, B, C withsingle-phase enclosures 101A, 101B, 101C, which are aligned parallel toone another and are segmented into line segments 101 having a segmentlength 101L. A least one and preferably each line segment 101 cancomprise at least one holding means 103, 104 arranged at a longitudinalposition 103 z, 104 z of the line segment 101 for holding thesingle-phase enclosures 101A, 101B, 101C of the line segment 101relative to one another. Preferably, a first holding means 103 can bearranged at a first longitudinal position 103 z of the line segment forholding the single-phase enclosures 101A, 101B, 101C of the line segment101 relative to one another at the first longitudinal position 103 z,and a second holding means 104 can be arranged at a second longitudinalposition 104 z of the line segment 101 for holding the single-phaseenclosures 101A, 101B, 101C of the line segment 101 relative to oneanother at the second longitudinal position 104 z. This allows to mountthe single-phase enclosures 101A. 101B, 101C of the line segment 101together and to form a unitary line-segment module 102.

The single-phase enclosures 101A, 101B, 101 C are preferably made frommetal and are separately gas-tight and lengthwise segmented. Eachenclosure 101A, 101B, 101C houses a central conductor 12 that issuspended in an insulation gas compartment 13. Thus, each line-segmentmodule 102 forms a fully functional section of the gas-insulated line100. The gas compartments 13 enclosed by the enclosures 101A, 101B, 101Care filled with an insulation gas at elevated pressure. Specifically,technical air (80% N2, 20% O2) as insulation gas can be used. Typicalinsulation gas pressures are in a range of 3 bar to 10 bar.

As shown in FIG. 2 , the three phases A, B, C can be arranged in atriangular setup and preferably on the same distance from the center zof the pipe 106. The pipe diameter is slightly bigger than the outsidediameter of the three phases A, B, C arranged in triangular shape.

As shown in FIGS. 2 to 5 , each holding means 103, 104, in particularthe first and second holding means 103 and 104, can comprise atriangular fixation element 108, in particular triangular fixation plate108, that is shaped and arranged to fit in an intermediate volumebetween the single-phase enclosures 101A, 101B, 101C and providesmounting means 108 a for mounting phase fixation elements 109 and/or formounting the moving means 105 thereon.

In embodiments, the fixation element 108 can be star-shaped with cutoutsthat match the outer diameter of the single-phase enclosures 101A, 101B,101C (or enclosure 1 or enclosure tubes 2, 3 as shown in FIG. 9, 10 ).The fixation element 108 can be placed in the center of the pipe 106.Phase fixation elements or bands 110 can be wrapped around eachsingle-phase enclosure 101A, 101B, 101C or enclosure 1 or enclosuretubes 2, 3 and fixed to the triangular fixation element 108.

The phase fixation elements 109 can have a partial-circular ring shapefor surroundingly fixing the single-phase enclosures 101A, 101B, 101Cand for being mounted, in particular screwed, to the triangular fixationelement 108.

In embodiments, the holdings means 103, 104, in particular the first andsecond holding means 103 and 104 and preferably the triangular fixationelement 108, can hold the three single-phase enclosures 101A, 101B, 101Cin a triangle, wherein the third phase C or its single-phase enclosure101C can be placed centered at the bottom of the triangle (e.g. with anangular tolerance of e.g. +−15°) and the first phase A or itssingle-phase enclosure 101A and the second phase B or its single-phaseenclosure 101 B are placed laterally to each other and above the thirdphase C or its single-phase enclosure 101C.

In embodiments thereof, first and second holding means 103, 104, inparticular the triangular fixation element 108, can hold the threesingle-phase enclosures 101A, 101B, 101C in a triangle, which, wheninscribed in a circle with 0° at the top, can have the first phase A atan angular position in a range of e.g. 285° to 310° and preferred ofapproximately 300°, the second phase B at an angular position in a rangeof e.g. 50° to 75° and preferred of approximately 60°, and the thirdphase C at an angular position in a range of e.g. 170° to 190° andpreferred of approximately 180°. Widening the distance or angle betweenthe phase enclosures 101A and 101B has the advantage to provide morespace for an optional supply duct 114.

In embodiments, a supply duct 114 can be arranged in a free space,preferably on an upper side and/or between the single-phase enclosures101A, 101B, 101C, and can be suitable for receiving at least oneselected from the group consisting of: power cable, network cable,fiber-optic cable, gas pressure supply tube, other media supply line,and other low-voltage cable. Thus, the supply duct 114 can be placed inthe gap between the phase enclosures 101A and 101B on top and fixed tothe triangular fixation element 108 and can run in parallel to thegas-insulated line 100.

In embodiments, the holdings means 103, 104, in particular the first andsecond holding means 103 and 104 and preferably their triangularfixation element 108, can each hold a first roller 105 a placed in a gapto the left and and a second roller 105 b placed in a gap to the rightof the third phase C or its single-phase enclosure 101C, wherein aheight of the first and second roller 105 a, 105 b is chosen to besuitable to carry the weight of the section or line-segment module 102of the gas-insulated line 100, in particular a height suitable to touchan inside surface of a pipe 106.

In embodiments, the first and second holding means 103, 104 can eachcomprise the first moving means 105 a, in particular the first roller105 a, arranged at an angular position, when inscribed in a circle with0° at the top, in a range of e.g. 110° to 135° and preferred ofapproximately 120°, and the second moving means 105 b, in particular thesecond roller 105 b, arranged at an angular position in a range of e.g.225° to 250° and preferred of approximately 240°.

As shown in FIGS. 2 and 5 , the moving means 105, in particular a firstroller 105 a; 105 c fixed to the first holding means 103 and a secondroller 105 b; 105 d fixed to the second holding means 104, can beequipped with a spring mechanism 107 to provide a resilient suspensionfor the line-segment module 102. As an alternative or in addition, themoving means 105 or rollers 105 a, 105 c; 105 b, 105 d can have aresilient surface layer, e.g. of 4 mm or more thickness, which alsoprovides or contributes to the resilient suspension for the line-segmentmodule 102. Thereby, the spring 107 and/or resilient surface layer ofeach roller 105 a, 105 b (and similar 105 c, 105 d in FIGS. 7 to 8 ) canbalance the weight of the line-segment module 102 on both rollers 105 a,105 b and compensate for bottom unevenness, obstacles, etc. Theresilient force in normal position can be chosen similar to half theweight of the line-segment module 102.

As shown in FIGS. 6 to 8 , the gas-insulated line 100 or itsline-segment modules 102 can comprise three phases A, B, C withsingle-phase enclosures 101A, 101B, 101C, wherein the holding means 103,104, in particular the first and second holding means 103, 104, hold thethree phases A, B, C in a linear arrangement, preferably side-by-side.In addition, at least a fourth phase, e.g. a reserve phase, can bearranged in the line-segment module 102 and can be held by the (firstand second) holding means 103, 104 in the linear arrangement,

As shown in FIGS. 7 to 8 , each holding means 103, 104, in particularthe first and second holding means 103 and 104, can comprise three phasefixation elements 110 fixed side-by-side to one another. In embodiments,each phase fixation element 110 can comprise a partial-circular upperholding ring 110 a and a partial-circular lower holding ring 110 b forembracing and thereby fixing the single-phase enclosure 101A, 101B, 101Cof the corresponding phase A, B, C.

Each holding means 103, 104 can comprise moving means 105, in particularrollers 105 c, 105 d, mounted at lateral end positions and/or atintermediate positions between phase fixation elements 109 of eachholding means 103, 104, respectively.

The system 200 is further and exemplarily discussed with respect to FIG.1 or FIG. 6 . As indicated therein, each line-segment module 102 andthus the assembly bled gas-insulated line 106 as a whole can rest on therollers 105 a, 105 b; 105 c, 105 d. The rollers 105 a, 105 b; 105 c, 105d can be placed with certain spacings, e.g. evenly spaced, along thegas-insulated line 100. Preferred spacings can be every few meters.

In embodiments of the system 200, the confined space 106 is notaccessible for personnel in upright position or is inaccessible topersonnel. Preferably, the confined space 106 can be connected to atleast one manhole 201 that is or are accessible by personnel forinstalling, maintaining and/or removing line-segment modules 102.

A pipe 106 (or tunnel or other laterally confined space 106) can be laidabove or below ground level 106 along the planned path for thegas-insulated line 100. The pipe 106 can be sealed and connected on eachend to a manhole 201. Additional manholes (not shown) may be used alongthe gas-insulated line 100 every few 100 m or at every turn. Themanholes 201 at each end are used to connect the gas-insulated line 100to e.g. air-insulated lines 205 via bushings 204 and/or verticalgas-insulated line sections 203, to other switchgear components or asubstation, or to high-voltage cables via cable terminations (notshown). The pipe 106 is preferably clean on the inside and water tight.The system 200 as a whole can be an energy transmission and distributionsystem 200.

The manholes 201 are used for assembly of the gas-insulated line 100 insections or segments 101, in particular line-segment modules 102. Eachsection or segment 101 or line-segment module 102 of a three-phasegas-insulated line 100, e.g. pre-assembled according to FIG. 2 , canhave a length of several meters and is lowered into the manhole 201.Pre-assembly or assembly of the line-segment module 102 as disclosedherein may also be done inside the manhole 201. The rollers 105 a, 105 bare then placed on the inside of the pipe 106, and the GIL section 101or line-segment module 102 is then rolled into the pipe 106 until theends reach the pipe entrance. At this point, the next GIL section orline-segment module 102 is lowered into the manhole 201 and all threephases A, B, C and an optional supply duct 114 are connected to theprevious line-segment module 102. The assembly is then pushed furtherinto the pipe 106 and the process repeats. For this process, the length201L of the manhole 201 can be chosen longer than the length 101L of theGIL section 101 or line-segment module 102. The manhole length can bechosen e.g. in a range of 6 m to 14 m and preferred 6 m to 8 m, and themodule length 101L can be chosen e.g. in a range of 2 m to 12 m,preferred 4 m to 10 m.

In embodiments of the system 200, the confined space 106 can e.g. beselected from the group consisting of: a pipe 106, an existing unusedpipe, a water pipe, a sewage pipe, a tunnel 106, an underground tunnel,a tunnel in soil, a tunnel underneath pavement, and combinationsthereof.

The at least one manhole 201 can be equipped with manhole equipment 202e.g. selected from the group consisting of: a mounting unit for theline-segment modules 102, a dismantling unit for the line-segmentmodules 102, a connection unit for connecting line-segment modules 102together and/or to length compensation elements 111 and/or toflexible-angle elements 113, a gas-filling device, a monitoring devicefor supervision of the gas-insulated line 100 during operation, an aircooling and blowing equipment, and combinations thereof.

Slim Flange Design

The co-pending International Application PCT/EP2020/070540 filed on thesame date by the same applicant, shall herewith be incorporated byreference in its entirety into this application. It refers to a slimintegrated flange design. Incorporation by reference includes thegeneral description, all FIGS. 1-6 and the related description, and allclaims, which are herewith deemed included by reference into thedescription as clauses.

The slim flange design 4 is exemplarily shown in FIG. 9 . Eachsingle-phase enclosure 101A, 101B, 101C of the gas-insulated line 100can comprise a first enclosure tube 2 and a second enclosure tube 3,both having a longitudinal axis z and a radial thickness d, andtherebetween a connection portion 4 for providing a gas tight connectionbetween a first end 20 of the first enclosure tube 2 and a second end 30of the second enclosure tube 3, wherein the connection portion 4provides a sealing element 5; 5 a, 5 b between the first end 20 and thesecond end 30 in such a manner that a gas-escape path L can be sealed ina gas-tight manner, wherein the gas-escape path L is formed between thefirst end 20 and the second end 30 and starts at an inside 6 of thefirst and second enclosure tube 2, 3 and ends at an outside 7 of thefirst and second enclosure tube 2, 3, the gas-escape path L has a firstsegment L1 running along a direction having a directional componentparallel to the longitudinal axis z, and the sealing element 5; 5 a, 5 bis provided in the first segment L1.

In embodiments, the first end 20 can comprise a first connection face 21and the second end 30 can comprise a mating second connection face 31,and the gasescape path L can be formed between the first connection face21 and the second connection face 31.

In another aspect of the integrated flange design 4, each single-phaseenclosure 101A, 101B, 101C of the gas-insulated line 100 can comprise afirst enclosure tube 2 and a second enclosure tube 3, both having alongitudinal axis z and a radial thickness d, and therebetween aconnection portion 4 for providing a gas-tight connection between afirst end 20 of the first enclosure tube 2 and a second end 30 of thesecond enclosure tube 3, wherein a first connection face 21, inparticular a first protrusion 22 and/or a first recession 23, is or areformed or machined into the first end 20, and a second mating connectionface 31, in particular a second protrusion 32 and/or a second recession33, is or are formed or machined into the second end 30.

In embodiments of the integrated flange design 4, before forming ormachining the first and second connection face 21, 31, the first end 20has the same inner and outer diameter as the first enclosure tube 2;and/or the second end 20 has the same inner and outer diameter as thesecond enclosure tube 3; and/or the first end 20 and the second end 30have the same inner and outer diameter, respectively. In particular, thefirst and second enclosure tubes 2, 3 can be made from metal and canhave a thickness of several mm, preferred in a range of 6 mm to 15 mm,more preferred 8 to 12 mm.

In embodiments, the connection portion 4 comprises a bracket 9, 9′surrounding the first end 20 and the second end 30, for providing anaxial holding force for holding the first end 20 and the second end 30together.

Embodiments of the gas-insulated line 100 disclosed herein also refer toa length compensation element or unit 111. Thermal expansion of thegas-insulated line 100 during operation can be compensated by providing:a first longitudinal fixation position 100 f, in particular first endposition 100 f, at which the gas-insulated line 100 is fixedly mountedto a first reference location, a second longitudinal fixation position100 g, in particular second end position 100 g, at which thegas-insulated line 100 is fixedly mounted to a second referencelocation, there-between a length compensation element 111 being arrangedin the gas-insulated line 100, in particular between two line-segmentmodules 102, and the moving means 105, in particular rollers 105 a, 105b; 105 c, 105 d, of the line-segment modules 102, which are arrangedbetween the first and second longitudinal fixation positions 100 f, 100g, being unblocked for allowing for small movements due to thermalexpansion or contraction of the gas-insulated line 100 between the firstand second longitudinal fixation positions 100 f, 100 g.

In embodiments, each single-phase enclosure 101A, 101B, 101C cancomprise at least one length compensation element 111 arranged at one ofthe connection portions 4 of the first and second enclosure tubes 2, 3,wherein the first segment L1 of the gas-escape path L is runningparallel to the longitudinal axis z of the single-phase enclosure 101A,101B, 101C, and at both ends of the first segment L1 an axial expansiongap 112 is provided for allowing relative movement of the first end 20of the first enclosure tube 2 and the second end 30 of the secondenclosure tube 3, in particular for compensating thermal elongation orcontraction or axial length tolerances of the first and/or secondenclosure tubes 2, 3 without compromising the gas-tight sealing betweenthe first end 2 and the second end 3. Favorable, the movement means orrollers 105; 105 a, 105 b, 105 c, 105 d are installed permanently andremain unblocked during the whole lifetime of the gas-insulated line100, in particular for compensating thermal expansion after installationor during operation of the gas-insulated line 100.

LIST OF DESIGNATIONS

-   100 gas-insulated line, gas-insulated apparatus-   100 d diameter of gas-insulated line, outer diameter, enveloping    diameter-   100 h height of gas-insulated line, outer height, maximal height-   100 w width of gas-insulated line, outer width, maximal width-   101 line-segment-   101A, 101B, 101C single-phase enclosures-   101L length of line-segment, length of line-segment module-   102 line-segment module-   102 e longitudinal end position of line-segment module-   103 first holding means-   103 z first longitudinal position-   104 second holding means-   104 z second longitudinal position-   105 moving means-   105 a first moving means, first roller-   105 b second moving means, second roller-   105 c moving means, roller(s)-   105 d moving means, roller(s)-   106 confined space, pipe, tunnel-   106 d diameter of confined space, inner diameter, minimal diameter-   106 h height of confined space, inner height, minimal height-   106 w width of confined space, inner width, minimal width-   107 spring mechanism for line-segment module-   108 triangular fixation element-   108 a mounting means-   109 phase fixation element-   110 phase fixation element-   110 a partial-circular upper holding ring-   110 b partial-circular lower holding ring-   111 length compensation element or unit-   112 axial expansion gap-   113 flexible-angle element or unit-   114 supply duct-   13 insulation gas compartment-   200 system comprising gas-insulated line arranged in confined space-   201 manhole-   201L manhole length-   202 manhole equipment-   203 vertical gas-insulated line section-   204 bushing-   205 high-voltage or medium-voltage line (gas-insulated or    air-insulated)-   206 ground level-   A, B, C phases, single-encapsulated phases-   x, y radial direction of the enclosure or of the medium-voltage or    high-voltage apparatus-   z longitudinal axis of the enclosure or of the medium-voltage or    high-voltage apparatus

Slim Flange Design

-   1 gas-tight enclosure, metal enclosure-   1A busbar, busduct, busduct segment, medium-voltage apparatus,    high-volt- age apparatus-   2 first enclosure tube-   2 a outside face of first enclosure tube-   2 b first indenture in 2 a, rectangular groove-   20 first end of first enclosure tube-   21 first connection face of first end-   22 first protrusion of first connection face at inside of enclosure-   22 i inner face of first protrusion-   22 o outer face of first protrusion-   23 first recession of first connection face at outside of enclosure-   3 second enclosure tube-   3 a outside face of second enclosure tube-   3 b, 3 b′ second indenture in 3 a, rectangular groove-   30 second end of second enclosure tube-   30 a rounded edges-   31 second connection face of second end-   32 second protrusion of second connection face at outside of    enclosure-   33 second recession of second connection face at inside of enclosure-   4 connection portion-   4 a first insert part of connection portion-   4 b second insert part of connection portion-   5 sealing element-   5 a first sealing ring, outside sealing ring-   5 b second sealing ring, inside sealing ring-   50 sealing groove-   6 inside of the enclosure tubes-   7 outside of the enclosure tubes-   8 spacer, post-type insulator, disk-shaped insulator, supporting    insulator, compartment insulator-   80 spacer groove-   9 bracket-   9′ prolonged bracket, sliding-tolerant bracket-   9 a axial slit in bracket-   9 b axial extension of bracket, bracket width-   9 c thickness of bracket (in radial direction)-   90 first rim of bracket-   91 second rim of bracket-   91′ modified second rim, sliding rim of bracket-   10 securing bar-   11 heat shrink tube-   12 conductor-   13 insulation gas compartment-   14 insert connection, welded connection-   100 f first longitudinal fixation position-   100 g second longitudinal fixation position-   100 m movable enclosure part-   111 length compensation element, length compensation unit-   112 axial expansion gap-   d radial thickness of the enclosure tubes or of their ends-   d′ radial thickness of connection portion (insert) of enclosure    tubes-   d″ reduced radial thickness of enclosure tube-   L gas-escape path-   L1 first segment of gas-escape path with axial directional component-   L2 second segment of gas-escape path with radial directional    component-   L2 i inner second segment of gas-escape path starting from inside of    enclosure-   L2 o outer second segment of gas-escape path ending at outside of    enclosure

1. A gas-insulated line having a longitudinal axis comprising phaseswith separately gas-tight single-phase enclosures that are alignedparallel to one another, and being segmented into line segments having asegment length, wherein at least one of the line segments comprises: atleast one holding means arranged at at least one longitudinal positionof the line segment for holding the single-phase enclosures of the linesegment relative to one another, thereby mounting the single-phaseenclosures of the line segment together and forming a unitaryline-segment module, and the line-segment module comprises moving meansfor facilitating movement of the line-segment module.
 2. Thegas-insulated line according to claim 1, comprising: a first holdingmeans at a first longitudinal position of the line segment for holdingthe single-phase enclosures of the line segment relative to one anotherat the first longitudinal position, a second holding means at a secondlongitudinal position of the line segment for holding the single-phaseenclosures of the line segment relative to one another at the secondlongitudinal position, and thereby mounting the single-phase enclosuresof the line segment together and forming the unitary line-segmentmodule.
 3. (canceled)
 4. The gas-insulated line according to claim 1,wherein the moving means comprise rollers for supporting and moving theline-segment module.
 5. The gas-insulate line according to claim 1,wherein the moving means are arranged in each holding means and areadapted to support and allow rolling the line-segment module in aconfined space and the confined space is not accessible for personnel inupright position or is inaccessible to personnel.
 6. The gas-insulatedline according to claim 1, wherein the moving means in particular afirst roller and a second roller in each holding means, are mountedpermanently on the line-segment module.
 7. The gas-insulated lineaccording to claim 1, wherein the moving means are mounted for at leastone of: inserting the line-segment module into the confined space duringinstallation, removing the line-segment module out of the confined spacefor maintenance or repair, compensating thermal expansion duringoperation of the gas-insulated line.
 8. The gas-insulated line accordingto claim 1, wherein in each holding means the moving means, inparticular a first roller and a second roller in each holding means, areequipped with a spring mechanism or have a resilient surface layer toprovide a resilient suspension for the line-segment module.
 9. Thegas-insulated line according to claim 1, comprising three phases withsingle-phase enclosures, wherein the first and second holding means holdthe three phases in a triangular arrangement, wherein each holding meanscomprises a triangular fixation element that is shaped and arranged tofit in an intermediate volume between the single-phase enclosures andprovides mounting means for mounting phase fixation elements and formounting the moving means thereon.
 10. (canceled)
 11. The gas-insulatedline according to claim 9, wherein the first and second holding means,hold the three single-phase enclosures in a triangle, wherein the thirdphase C is placed centered at the bottom and the first phase A and thesecond phase B are placed laterally to each other and above the thirdphase C, and each holding means holds a first moving means or rollerplaced in a gap to the left of the third phase C and a second movingmeans or roller to the right of the third phase C, wherein a height ofthe first and second roller is chosen to be suitable to carry the weightof the line-segment module.
 12. (canceled)
 13. (canceled)
 14. Thegas-insulated line according to claim 2, comprising at least threephases with single-phase enclosures, and the first and second holdingmeans hold the three phases in a linear arrangement, wherein eachholding means comprises three phase fixation elements fixed side-by-sideto one another.
 15. (canceled)
 16. The gas-insulated line according toclaim 14, wherein each holding means comprises the moving means, inparticular rollers, mounted at lateral end positions and/or atintermediate positions between phase fixation elements of each holdingmeans, respectively.
 17. The gas-insulated line according to claim 1,wherein each single-phase enclosure of the gas-insulated line comprisesa first enclosure tube and a second enclosure tube, both having alongitudinal axis and a radial thickness, and therebetween a connectionportion for providing a gas-tight connection between a first end of thefirst enclosure tube and a second end of the second enclosure tube,wherein the connection portion provides a sealing element between thefirst end and the second end in such a manner that a gas-escape path issealed in a gas-tight manner, the gas-escape path is formed between thefirst end and the second end and starts at an inside of the first andsecond enclosure tube and ends at an outside of the first and secondenclosure tube, the gas-escape path has a first segment running along adirection having a directional component parallel to the longitudinalaxis, and the sealing element is provided in the first segment.
 18. Thegas-insulated line according to claim 17, wherein the first endcomprises a first connection face and the second end comprises a matingsecond connection face, and the gas-escape path is formed between thefirst connection face and the second connection face.
 19. Thegas-insulated line according to claim 1, wherein each single-phaseenclosure of the gas-insulated line comprises a first enclosure tube anda second enclosure tube, both having a longitudinal axis and a radialthickness, and therebetween a connection portion for providing agas-tight connection between a first end of the first enclosure tube anda second end of the second enclosure tube, wherein a first connectionface is or are formed or machined into the first end, and a secondmating connection face is or are formed or machined into the second end.20. (canceled)
 21. The gas-insulated line according to claim 17, whereinthe connection portion comprises a bracket surrounding the first end andthe second end, for providing an axial holding force for holding thefirst end and the second end together.
 22. The gas-insulated lineaccording to claim 1, wherein thermal expansion of the gas-insulatedline during operation is compensated by providing: a first longitudinalfixation position, at which the gas-insulated line is fixedly mounted toa first reference location, a second longitudinal fixation position, atwhich the gas-insulated line is fixedly mounted to a second referencelocation, there-between a length compensation element being arranged inthe gas-insulated line, and the moving means, in particular rollers, ofthe line-segment modules, which are arranged between the first andsecond longitudinal fixation positions, being unblocked for allowing forsmall movements due to thermal expansion or contraction of thegas-insulated line between the first and second longitudinal fixationpositions.
 23. The gas-insulated line according to claim 17, whereineach single-phase enclosure comprises at least one length compensationelement arranged at one of the connection portions of the first andsecond enclosure tubes, wherein the first segment of the gas-escape pathis running parallel to the longitudinal axis of the single-phaseenclosure, and at both ends of the first segment an axial expansion gapis provided for allowing relative movement of the first end of the firstenclosure tube and the second end of the second enclosure tube forcompensating thermal elongation or contraction or axial lengthtolerances of the first and second enclosure tubes without compromisingthe gas-tight sealing between the first end and the second end.
 24. Thegas-insulated line according to claim 1, wherein a flexible-angle unitis present in the gas-insulated line to provide a non-straightgas-insulated line.
 25. The gas-insulated line according to claim 1,wherein the segment length is in a range of 2 m to 12 m, preferred in arange of 4 m to 10 m.
 26. The gas-insulated line according to claim 1,wherein a supply duct is arranged in a free space, preferably on anupper side of or between the single-phase enclosures, and is suitablefor receiving at least one selected from the group consisting of: powercable, network cable, fiber-optic cable, gas pressure supply tube, othermedia supply line, and other low-voltage cable.
 27. (canceled) 28.(canceled)
 29. (canceled)
 30. A system, in particular energytransmission and distribution system, comprising a gas-insulated linehaving line-segment modules according to claim 1, and a confined spaceproviding a volume for accommodating the gas-insulated line.
 31. Thesystem according to claim 30, wherein the confined space is selectedfrom the group consisting of: a pipe, an existing unused pipe, a waterpipe, a sewage pipe, a tunnel, an underground tunnel, a tunnel in soil,a tunnel underneath pavement, and combinations thereof.
 32. The systemaccording to claim 30, wherein the gas-insulated line is in amulti-lateral arrangement of the phases and the confined space has aclear cross section having an at least partially rounded shape or an atleast partially circular shape; or wherein the gas-insulated line is ina linear arrangement of at least three phases, and the confined spacehas a clear cross section having a flat bottom.
 33. (canceled) 34.(canceled)
 35. (canceled)
 36. The system according to claim 30, whereinthe confined space is not accessible for personnel in upright positionor is inaccessible to personnel.
 37. The system according to claim 30,the system further comprising at least one manhole connected to theconfined space and being accessible by personnel for installing,maintaining and/or removing line-segment modules, wherein the at leastone manhole is at a starting position, an end position, and/or anintermediate position of the gas-insulated line and has a manhole lengththat is larger than the segment length.
 38. (canceled)
 39. (canceled)40. The system according to claim 30, comprising further electricalenergy transmission and distribution components, such as: a verticalgas-insulated line section, a bushing, a high-voltage or medium-voltageline isolated in gas or air, a switchgear component, a substation. 41.(canceled)
 42. A method for installing a gas-insulated line according toclaim 1 in a confined space, the gas-insulated line having alongitudinal axis, comprising phases with separately gas-tightsingle-phase enclosures and being segmented into line segment, themethod comprising the method elements of: a. aligning three single-phaseenclosures of a line segment in parallel to one another, b. fixing thethree single-phase enclosures together by a first holding means at afirst longitudinal position of the line segment and by a second holdingmeans at a second longitudinal position of the line segment, therebyforming a unitary line-segment module, c. connecting the line-segmentmodule to an end of an already assembled portion of the gas-insulatedline arranged in a confined space, e.g. a pipe or tunnel, and h.providing moving rollers, permanently mounted on the at least oneholding means.
 43. The method of claim 42, wherein the method element c.comprises the method elements d. and e.: d. inserting a formed ormachined end of the line-segment module into a formed or machined end ofthe already assembled portion of the gas-insulated line for providing aflange-connection, and e. securing the flange-connection by anelastically openable and closable bracket, and optionally securing thebracket by a securing bar and/or a heat shrink tube.
 44. The method ofclaim 42, comprising at least one method element of: f. filling a gasvolume of the three single-phase enclosures with an insulation gas at anelevated gas pressure, in particular air, SF₆, an alternative gas or gasmixtures, or a combination thereof at an over-pressure in a range of 3bar to 8 bars. g. arranging a supply duct on top of the line-segmentmodule and connecting it to a mating end of a supply duet of the alreadyassembled portion of the gas-insulated line, and h. moving or rollingthe gas-insulated line with the connected line-segment module by apushing or dragging force into the confined space.
 45. (canceled) 46.(canceled)
 47. The method of claim 42, wherein the moving means, inparticular rollers, are used for at least one of: inserting theline-segment module into the confined space during installation,removing the line-segment module out of the confined space formaintenance or repair, and compensating thermal expansion afterinstallation or during operation of the gas-insulated line.
 48. Thegas-insulated line according to claim 1, the line-segment module beingor comprising at least one of: a gas-insulated busbar; a gas-insulatedconnection element; a gas-insulated switchgear such as disconnectors,circuit breakers; or other electrical component.